Method for producing sheet supported coiled conductors

ABSTRACT

THIS DISCLOSURE RELATES TO A METHOD FOR PRODUCING SHEET SUPPROTED COILED CONDUCTORS AND ALSO TO VARIOUS CONSTRUCTIONS OF THESE SHEET SUPPORTED COILED CONDUCTORS. IN THE METHOD, THE COILED CONDUCTORS EACH WOUND AROUND A CORE MATERIAL ARE INTERPOSED BETWEEN A REQUIRED NUMBER OF SUPPORTING SHEETS MADE OF A MATERIAL NOT SOLUBLE IN A DISSOLVING LIQUID FOR THE CORE MATERIAL AND HAVING A PLURALITY OF CUTOUT PORTIONS THERETHROUGH SO THAT A SUBSTANTIAL PART OF THE COILED CONDUCTORS IS EXPOSES THROUGH THE CUTOUT PORTIONS, AND THE WHOLE OF THE COILED CONDUCTORS INTERPOSED BETWEEN THE SUPPORTING SHEETS IS IMMERSED INTO THE DISSOLVING LIQUID FOR THE CORE MATERIAL SO THAT THE CORE MATERIAL IS THEREBY DISSOLVED AND REMOVED FROM THE COILED CONDUTORS.

Feb. 6, 1973 MASANOBU AIZAWA ETAL 3,714,691

METHOD FOR PRODUCING SHEET SUPPORTED COILED CONDUCTO RS Filed Nov. 18,1970 2 Sheets-Sheet l Feb 6, 1973" MASANOBU AIZAWA EI'AL 3,714,591

METHOD FOR PRODUCING SHEET SUPPORTED COILED CONDUCTOR Filed Nov. 18,1970 2 g Japan Filed Nov. 18, 1970, Ser. No. 90,602 Int. Cl. H013 9/18,9/36 US. Cl. 2925.15 Claims ABSTRACT OF THE DISCLOSURE This disclosurerelates to a method for producing sheet supported coiled conductors andalso to various constructions of these sheet supported coiledconductors. In the method, the coiled conductors each wound around acore material are interposed between a required number of supportingsheets made of a material not soluble in a dissolving liquid for thecore material and having a plurality of cutout portions therethrough sothat a substantial part of the coiled conductors is exposed through thecutout portions, and the whole of the coiled conductors interposedbetween the supporting sheets is immersed into the dissolving liquid forthe core material so that the core material is thereby dissolved andremoved from the coiled conductors.

BACKGROUND OF THE INVENTION This invention relates generally to a methodfor producing a sheet supported coiled conductor and improvedconstructions of the sheet supported coiled conductor produced by themethod.

Heretofore, coiled conductors such as tungsten filaments employed inelectric lamps are produced firstly by winding each of the conductorsaround a suitable core material such as copper wire or iron wire or rodand thereafter dissolving the core material away from the coiledconductors employing a dissolving solution such as aqua regia.

However, in usual cases, the coiled conductors thus produced have beenextremely fragile and difficult in handling because they may be easilydeformed or partly elongated permanently or cut. Furthermore, when thecoiled conductors are of an extremely minute size to the extent thatthey may be hardly visible by naked eye, handling of the coiledconductors has been more diflicult because they may be easily entangledtogether, and when the conductors are once entangled, it is toodifficult to disentangle these coiled conductors because a slight pullof such weak conductors may easily cause partial elongation ordeformation of these conductors and electrical resistance per length ofthe conductors may be thereby varied, thus causing irregularity in theillumination of the lamps wherein these filaments are employed.

SUMMARY OF THE INVENTION Therefore, the primary object of the presentinvention is to provide an improved method for producing sheet supportedcoiled conductors wherein all of the difiiculties found in handling theconventional coiled conductors can be substantially eliminated.

Another object of the present invention is to provide an improved methodfor producing sheet supported coiled conductors, which is adapted inmass-production of such conductors.

Still another object of the present invention is to provide an improvedmethod for producing sheet supported coiled conductors, wherein theconductors still including the core material are handled to be supportedin the United States Patent 0 3,714,691 Patented Feb. 6, 1973 "icesupporting sheets and the core material is thereafter dissolved awayfrom the coiled conductors.

Still another object of the invention is to provide an improvedconstruction of the sheet supported coiled conductors which are adaptedto be employed in various fields of applications.

These and other objects of the present invention can be achieved by animproved method for producing sheet supported coiled conductors, whichcomprises the steps of forming coiled conductors each wound around acore material soluble in a dissolving liquid, providing a requirednumber of supporting sheets made of a material not soluble in thedissolving liquid for the core material and having a plurality of cutoutportions formed through the supporting sheets, interposing the coiledconductors still including the core material between each of thesupporting sheets so that a substantial part of the coiled conductors isexposed through the cutout portions of the supporting sheets, andimmersing the whole of the coiled conductors and the supporting sheetsinto the liquid for dissolving the core material so that the corematerial is removed from the coiled conductors and the required sheetsupported coiled conductors are thereby obtained.

In another aspect of the present invention, there are provided variousforms of the sheet supported coiled conductors produced in accordancewith the above described production method, which comprises a requirednumber of coiled conductors which are, in their initial stage of theproduction, wound around core materials; a plurality of supportingsheets made of a material not soluble in a dissolving liquid for thecore materials and having a required number of cutout portions; theabove mentioned coiled conductors being interposed between thesupporting sheets so that a substantial portion of the coiled conductorsis exposed through the cutout portions of the supporting sheets; wherebywhen the coiled conductors and the supporting sheets are immersed intothe liquid, the core materials are dissolved away from the coiledconductors.

The invention will be better understood from the following detaileddescription of the invention when read in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS ;IIII of the sheet supported coiledconductors shown in DETAILED DESCRIPTION OF THE INVENTION Referring nowto FIG. 1, which shows a coiled conductor produced by a method inaccordance with the present invention, there is indicated the coilconductor 1 in its initial stage wound around a core material 2 andinterposed between a pair of sheets, 3, 3' of a material not soluble ina liquid such as aqua regia which is employed for dissolving the corematerial 2. Through the pair of sheets 3, 3, a plurality of windows 4,4' are pro- 'vided so that most of the part of the coiled conductor 1may be exposed through these windows 4, 4'. Through the pair of thesheets, 3, 3', there are also provided a required number of perforations5, 5' of a far smaller size which are employed for the guidance ofaligning the windows 4 on the sheet 3 with the windows 4' on the sheet3'.

When the whole assembly of the coiled conductor 1 and the sheets 3, 3'is immersed in a dissolving liquid for the core material, the corematerial 2 such as iron or copper is dissolved into the liquid, and thecoiled conductor 1 remains behind interposed between the two sheets. 3,3' of a material not soluble in the dissolving liquid such as aqua regiaas indicated in FIG. 2.

FIGS. 3 through 8 show various modifications of the coiled conductorsproduced through the method according to the present invention. Withinthese drawings, FIGS.

3 and 4 indicate examples of the coil conductors held between two sheetsof the above described material. In these examples, a plurality of rowsof windows 4, 4' are provided, and a plurality of coiled conductors of aconsiderable length or of a length slightly larger than the diagonal ofthe window are held between the two sheets 3, 3'. In a specific exampleof FIG. 5, the coiled conductors 1 are disposed in such a manner whereinthe arrangement thereof in FIG. 3 is superposed on the arrangement shownin FIG. 4. In another example shown in FIG. 6, there is indicated stillanother construction of the conductor holding sheet wherein a pluralityof cutout portions 4a and notches 5a and projections 6, 6' are providedinstead of the above described windows 4, 4' and small perforations 5,5'. Furthermore, as shown in FIGS. 7 and 8, the windows 4' provided inthe above described examples in one of the two sheets 3' may be omitted.In such a case, the small perforations 5, 5' may also be omitted becausethere is no necessity of aligning windows as in the cases of theprevious examples.

Although the invention has been described with respect to preferredexamples of the conuctor arrangement, it will be apparent to thoseskilled in the art that various modifications or alterations may also becarried out on these arrangements without departing from the spirit andscope of the present invention as defined hereinbelow.

What is claimed is:

1. A method for producing sheet supported coiled conductors comprisingthe steps of forming said coiled conductors each wound around a corematerial, providing a required number of supporting sheets made of amaterial not soluble in a dissolving liquid for the core material andhaving a plurality of cutout portions through the supporting sheets,interposing said coiled conductors including said core material betweensaid supporting sheets so that a substantial part of the coiledconductor is exposed through the cutout portions, and immersing saidcoiled conductors held in the supporting sheets into said dissolvingliquid for the core material so that the core material is removed fromthe coiled conductors.

2. A method as defined in claim 1 wherein said number of supportingsheets are slected to be two and said cutout portions are providedthrough each of said two sheets at the aligning positions.

3. A method as defined in claim 1 wherein said cutout portions are inthe form of a window.

4. A method as defined in claim 1 wherein said cutout portions are inthe form of notches.

5. A method as defined in claim 1 wherein said coiled conductors aretungsten filaments, said core material is a copper wire, and saiddissolving liquid is aqua regia.

References Cited UNITED STATES PATENTS 2,380,525 7/1945 Hirmann 29-25173,346,761 10/1967 Ackerman 2925.l7 X 3,103,061 9/ 1963 Fonoroff et a].2.9'l55.55

I. SPENCER OVERHOLSER, Primary Examiner R. B. LAZARUS, AssistantExaminer U.S. CL X.R.

